Prevention of wounds associated with immobility and promoting of healing of existing wounds on an immobilized or bedridden patient can be a resource consuming challenge for healthcare providers. Undesirable pathological side effects can result from a patient's bedridden condition which health care providers must attempt to avoid during the patient's immobilization. Of primary concern are pressure ulcers, or bedsores, which result from extended contact between pressure points along the patient's body and the supporting surface, such as a bed mattress. The weight of the patient on these contact areas serves to compress the tissue in these areas. The areas of compressed tissue experience reduced blood circulation. The lack of oxygenated blood can lead to death of cells in the compressed region of tissue. A pressure ulcer may first appear as an area of non-blanch able erythematic and may progress to a deep crater wound that can involve muscle, bone and joints. These wounds typically develop over a bony prominence due to the interface with the patient supporting surface. Left untreated, pressure ulcers can lead to sepsis, which can cause death.
Pressure ulcers can be caused not only by pressure forces against tissue, but also by forces of shear, friction, or maceration applied to the tissue of patient, alone or in combination. These other forces may be generated anytime force is applied to the patient or bed tending to move them relative to each other while contact between the patient and surface, tending to hold the tissue, remains.
Also, if the patient has injuries on or adjacent to the contact areas of tissue, the reduced blood circulation at those pressure points can interfere with the proper healing of those injuries. In short, any medical condition that immobilizes a patient, temporary or chronic, can ultimately lead to the localized circulation problems described above. Any condition that decreases a patient's ability to make positional changes can cause the patient to be easily susceptible to the wounds of immobility.
To alleviate the potential for formation of pressure ulcers or wounds on an immobilized patient, it has been common practice to periodically move the position of the patient's body (typically in bed) so that the pressure of the patient's weight is relieved from the current tissue pressure points and shifted to new pressure points so that blood flow can resume in the formerly pressurized areas. A complication of moving the patient to a new position in the bed is that the immobilized patient cannot exert him or herself to help move their own body. Therefore, the healthcare provider must frequently move the entire patients weight of the patient alone, which can be a difficult task that presents the risk of exertion related injuries to the health care worker. Also, movement of the patient relative to the bed without fully lifting the body from the bed can leave tissue areas under high shear and frictional forces, which cause pressure ulcers. In a large healthcare facility with multiple immobilized patients, manually moving the position of the bedridden patients can consume a significant portion of the healthcare staff's time. Additionally, a patient may have additional injuries or complications requiring special positioning such that certain areas of the body do not experience the pressure of the patient's weight. It may be difficult to manually move the patient's body to the ideal position for proper healing and patient comfort.
Various mechanisms are available for assisting healthcare providers and alleviating the effects of sustained active pressure points on an immobilized patient's body. Patient turning beds provide a patient supporting surface that is capable of rotating about a longitudinal axis of the bed from side-to-side, out of the horizontal plane. The rotation serves to shift the patient's body weight from one side to another in an effort to help reduce the effects of localized tissue pressure points on the patient's body where it meets the supporting surface of the bed. U.S. Pat. No. 5,103,511 (Sequin) discloses such an oscillatory bed.
There are several shortcomings in the use of the turning bed. The patient must be secured in the oscillatory bed so that he or she does not roll out of the bed when it is rotated to a plane that defines an angle away from the horizontal. The bed does not serve to change the position of the patient's body within the bed but only serves to relieve pressure forces on the half of the patient's body above the horizontal plane. With the patient's body still in contact with the supporting surface shear and frictional forces are still exerted on the patient's tissue and may be increased as the patient's body tends to slide across the inclined surface of the turned bed. Additionally, the areas of the body that can be relieved of pressure are limited only to a portion, which lies above the horizontal plane when the bed is rotated.
Another disadvantage of the turning bed is that it requires a substantial expense in equipment and that an entire specialized bed must be obtained (rented, leased, purchased etc.). A patient must be in a facility that has such a bed and must be moved into the specialized bed in order to use it, which can be difficult for the immobilized patient and time consuming for the staff. Furthermore, because the entire bed is not easily moved, accommodations for immobilized patients are limited to where such beds can be located. In instances of patient care to be given in the patient's home, a large mechanical turning bed may not be able to fit in a small sized home. Another potential issue experienced with some turning beds is a restrictive patient weight limitation.
Another type of specialized bed intended to minimize pressure ulcers is marketed under the name Clinitron®. This type of bed utilizes a base tub of silicone beads with a protective containment covering on top. Air is blown from the bottom upward through the sand to cause the sand to flow and create a fluid-like supporting surface. The patient lies on the protective top covering supported by the bed of fluidized sand. Although the Clinitron approach may tend to equalize the compressive forces across all points of the patient's body, because body contact is maintained with the supporting surface, shear and frictional forces can still exist, which can lead to pressure ulcers.
U.S. Pat. No. 5,774,947 (Liu) discloses a turning mattress formed from inflatable bladders, each having a right and left cell separated by a central diaphragm. The left and right sides of the bladders can be alternately inflated to rotate the patient's body away from the horizontal plane to unweigh that portion of the patient's body which lies above the horizontal plane in the manner of the turning mattress described above. Because the turning mattress is used on a hospital bed, the portability issues raised above in connection with the above-described turning bed still exist. Also, as mentioned above, the turning mattress serves to move the patient only by rotation about a single longitudinal axis and does not serve to lift the patient away from the support surface. Therefore, bony prominences susceptible to pressure ulcers, remain in contact with the supporting surface and forces are translated to the tissue.
U.S. Pat. No. 4,986,260 (Iams et al.) and U.S. Pat. No. 6,014,784 (Taylor et al.) disclose pads having multiple inflatable bladders controlled to provide a continuously movable surface upon which an immobilized patient's body can rest. The movement of the inflatable bladder surfaces addresses the problem of continuous pressure at tissue pressure points on the body. An additional problem with devices using multiple bladders is that the patient's body can slip between the bladders diminishing the intended effectiveness of the device and potentially creating discomfort for the patient. Also, the disclosed devices do not operate to turn and reposition the patient's body.